A poorly designed network has increased support costs, reduced service availability, and limited support for new applications and solutions. VLANs provide segmentation and organizational flexibility. The following chapter will introduce VLANs and Trunks. Inviting you to refer. | Medium-Sized Switched Network Construction Implementing VLANs and Trunks Issues in a Poorly Designed Network Unbounded failure domains Large broadcast domains Large amount of unknown MAC unicast traffic Unbounded multicast traffic Management and support challenges Possible security vulnerabilities VLAN Overview VLAN = Broadcast Domain = Logical Network (Subnet) Segmentation Flexibility Security Purpose: Emphasize: A VLAN is a broadcast domain. Note: In order to have inter-VLAN communications, a router is required. Designing VLANs for an Organization VLAN design must take into consideration the implementation of a hierarchical network addressing scheme. The benefits of hierarchical addressing are: Ease of management and troubleshooting Minimization of errors Guidelines for Applying IP Address Space Allocate one IP subnet per VLAN. Allocate IP address spaces in contiguous blocks. Network Traffic Types Traffic types to consider when designating VLANs: Network management IP telephony IP Multicast Normal data Scavenger class Advantages of Voice VLANs Phones segmented in separate logical networks Provides network segmentation and control Allows administrators to create and enforce QoS Lets administrators add and enforce security policies VLAN Operation VLAN Membership Modes Note: Once a port has been assigned to a VLAN, it cannot send or receive traffic from devices in another VLAN without the intervention of a Layer 3 device like a router. The 1900 can’t be configure as the VMPS. A CiscoWorks 2000 or CWSI management station or a Catalyst 5000 switch can be configured as the VMPS. In the future, dynamic VLANs may also offer membership based on other criteria such as protocol or application. Dynamic VLANs are covered in the Managing Cisco Switched Internetworks class. Trunking Frame Understanding Native VLANs VTP Features Cannot create, change, or delete VLANs Sends and forwards advertisements Synchronizes Create VLANs Modify VLANs Delete . | Medium-Sized Switched Network Construction Implementing VLANs and Trunks Issues in a Poorly Designed Network Unbounded failure domains Large broadcast domains Large amount of unknown MAC unicast traffic Unbounded multicast traffic Management and support challenges Possible security vulnerabilities VLAN Overview VLAN = Broadcast Domain = Logical Network (Subnet) Segmentation Flexibility Security Purpose: Emphasize: A VLAN is a broadcast domain. Note: In order to have inter-VLAN communications, a router is required. Designing VLANs for an Organization VLAN design must take into consideration the implementation of a hierarchical network addressing scheme. The benefits of hierarchical addressing are: Ease of management and troubleshooting Minimization of errors Guidelines for Applying IP Address Space Allocate one IP subnet per VLAN. Allocate IP address spaces in contiguous blocks. Network Traffic Types Traffic types to consider when designating VLANs: Network management IP .
